Engineering and Technology Journal

The Westergaard half-space problem has been solved using the potential theory in this work. It is a classical theme in elasticity theory that seeks to find the displacements and stresses in the half-space caused by known boundary loads. It has important applications in analyzing stresses and displacement fields in soil due to applied points and distributed loads on the boundary caused by structures placed on the soil. It is governed by stress–strain, strain-displacement, and equilibrium equations. Horizontal inextensibility is assumed in developing the problem, simplifying the displacement formulation to a three-dimensional (3D) Laplace equation. The potential theory is applied to find the vertical displacement. Stress–displacement equations obtained from the simultaneous use of the kinematic and stress-strain equations are used to obtain the stress fields. The specific problem of point load at the origin was considered and solved. The equilibrium of internal vertical stresses and the external vertical load is used to find the integration constant. Hence, vertical displacements were found. The stress fields were found from the stress–displacement equations. The expressions for the vertical displacements and stresses were found to be exact within the framework of the theory used, as they satisfied all the governing equations of the problem. However, the solutions become unbounded at the origin due to the singularity of the vertical displacement and stresses. The obtained solutions are identical to previously obtained solutions.

The horizontally curved box girder bridges are considered important nowadays because of their low cost compared to the load capacity and torsion moments that they can carry. This study presents a finite element analysis of a continuous box girder bridge using CSI finite element bridge software. Three spans with 40 m length, 12.5 m width, and 2.3 m height are studied. The analysis included different radii of curvature with different loading locations along the transverse direction of a cross-section. Several conclusions were reached, the most important of which is that the torsional moments in the outer face are superior to the inner face, even when loading near the inner face. That is, the torsional moments are affected more by the radius of curvature amount than by the location of the load. In general, the maximum torsional moments increase with the decrease of the curvature radius in the outer face. Nevertheless, the maximum torsional moments decrease with the decrease of the curvature radius in the inner face, except for the case of the curvature radius of 100 m. That can be attributed to the fact that the radius of curvature in this case is considered sharp, resulting in high torsional moments.

Soft clayey soils present geotechnical engineering challenges with significant stability and settlement. Various methods are employed to enhance the geotechnical properties of these soils. Heating and grouting are the methods used to improve such soil. A new heating and cement grouting system using gas as a source of heating through boreholes and Portland cement for grouting was designed and manufactured to enhance the soft soil. Different parameters were investigated, including the shear strength and the angle of internal friction, as well as the water/cement ratio, W/C (0.5, 0.75, 1, 1.25, 1.5, and 1.75), and the period of curing (3, 14, and 28 days). The results showed the shear strength and angle of internal friction increased from 14 to 300 kPa and 0 to 50 degrees, respectively. If only the heating system is running, the strength and behavior of the soil will improve via heated and cement grouting with a water/cement ratio. If the w/c ratio increases from 0 to 1.25, the ultimate bearing capacity ratio (qu treated/qu untreated) increases from 6.5 to 14.3 at 15% settlement. However, when the water/cement ratio increases from 1.25 to 1.75, the ultimate bearing capacity ratio (qu treated/qu untreated) decreases from 14.3 to 11.4. The ultimate bearing capacity ratio improves with increasing curative time. It climbs from 14.3 to 19.6 during 3 to 28 days for cement grouting models, while the ultimate bearing capacity ratio grows from 6.5 to 7 during 3 to 28 days for heating process models only, at 15% settlement.

Seismic activity has emerged as a mostly attractive issue for researchers and engineers, particularly in light of the recent occurrence of severe earthquakes worldwide, such as those felt in Turkey and Syria. Most entities prone to seismic damage are the structures. Any type of structure consists of a composite system involving structure, foundation, and soil. Previously, numerical and analytical methods for dynamic seismic analysis of structures ignored the impact of this system during earthquakes. In other words, soil-structure interaction (SSI) was ignored. Moreover, another important factor that was not considered is the interaction between structures and soil, or what is called structure-soil-structure interaction (SSSI), which usually occurs between two adjacent structures. This research aims to comprehensively understand the SSSI by performing a series of dynamic tests using a shaking table system. The tests concentrate on the effect of height on the dynamic behavior between two adjacent steel structures rested on sand soil. This study employed four novel small-scale multi-degree-of-freedom steel structure models: three, four, and five-story steel structures against a three-story steel structure. The results indicated that the tallest building had the maximum effect on the shorter one, especially on the top displacement with a peak value of 3.82 cm, top acceleration with a peak value of about 0.2 g, and foundation rotation with a peak value of around 1 degree. However, the effect of the structure height has a reverse impact on the soil pressure beneath the foundation of the shortest structure since the largest pressure response was recorded for the effect of the shortest similar adjacent building with a peak value of 8.8 kPa. In comparison, the highest building has the lowest effect on the shortest building, with a peak value of 6 kPa.

Quartz powder is used in ultra-high-performance concrete to improve granular packing, but repeated inhalation during manufacture can cause health issues. The mechanical properties of UHPC are influenced by the post-setting curing method. A hypothesis suggests limestone powder could be a viable filler to mitigate these issues under three different curing regimes, replacing quartz powder of similar size. The study assessed 18 mixtures with different w/b ratios for flow characteristics and compressive strength after 7 and 28 days of curing under various conditions. Limestone powder positively impacted compressive strength and had fresh properties. A two-factor interaction model accurately correlated variables and responses. Numerical optimization was performed to find the optimal mixture with proper flow and the highest compressive strength. The use of 150 kg/m3 of locally sourced limestone powder in the mixture with a w/b ratio equal to 0.198 and a 48hr-90°C curing regime can be considered the optimal amount to secure the greatest modeling compressive strength (169.10 MPa at 7 days and 181.71 MPa at 28 days), fulfilling the limit values of spread flow (220 mm) with the increasing percentage ratio of 67% and 49% at 7-days and 28-days ages under 90°C heat curing when the w/b equals 0.198.

Flexible pavements may be strengthened and enhanced incrementally to meet traffic needs, making them preferable to cement concrete roadways. Due to the rise of poor-quality bituminous pavements, Nigeria is promoting concrete pavements. Concrete pavements are becoming more popular because of their durability and ability to withstand heavy traffic and harsh environmental conditions. The primary objective of this study is to provide a comprehensive comparative analysis of both flexible and rigid pavement suitability, considering various parameters such as material characteristics, load-bearing capacity, longevity, and cost-effectiveness. The pavement structure used for the project meets the Federal Ministry of Works Highway Manual Part 1, Design Volume III specifications, with a few compositional adjustments. The study contains cost estimates for numerous parts of flexible pavement design, such as using a concrete wearing course, a bitumen emulsion tack coat, a concrete binder course, and an MC 1 cutback bitumen prime coat. The expenditure associated with the construction of flexible pavement amounts to 1,760,293,155.18 N, while the anticipated cost for the construction of rigid pavement is projected at 2,725,765,337.00 N. In percentage terms, rigid pavement costs 64% more than flexible pavement. Flexible pavement costs are based on supply, construction, and finish unit rates. The projected flexible pavement cost includes labor, materials, and plant expenditures. Reinforcing and concrete costs are estimated in rigid pavement studies. The analysis examines plant, people, and permanent material expenses. The research gives detailed pavement structural design and construction cost estimates for the road project, enabling informed pavement structure decisions.

The incorporation of fibers into engineered cementitious composite concrete imparts flexibility to the material. Therefore, using different types and contents of polymeric fibers would affect the behavior of such concrete types, and it is worth contemplating. The present research aims to study the flexural strength and the strain capacity of engineered cementitious composite concrete produced with polyvinyl alcohol fibers (PVA) and polypropylene fibers (PP) with different volume fractions (1%, 1.5%, and 2%). Six mixes of engineered cementitious composite concrete of three grades of strengths, 30, 45, and 60 MPa, were produced. Results revealed that mixes of 60 MPa with 2% PVA fibers recorded the highest strain capacity, which reached (17.6%) compared to mixes of 60 MPa with 2% PP fibers. The maximum enhancement in the flexural strength was (4.3%),(6%), and (23%) for mixes of 30 MPa, 45 MPa and 60 MPa. This enhancement may open the horizon for using high-strength engineered cementitious composite concrete reinforced with PVA fibers in structural applications exposed to flexural strength, providing a lighter weight due to the exclusion of bar reinforcement. Also, its high strain capacity reduces the tendency for microcracks formation. The standard deviation error bars for the average flexural strengths of bendable concrete mixes with different fiber contents and types show no differences when comparing the same strength and fiber types. For example, mixes of 60 MPa with PVA fibers give less than 2 MPa standard deviation when compared for different fiber volume fractions.

Climate change plays a crucial role in shaping the hydrological dynamics of rivers owing to its immediate implications on the driving meteorological parameters. Therefore, Understanding climate change and its implications is essential for sustainable water resource management. This study aims to assess the extent of climate change and its effects on streamflow in the Mosul Dam watershed Under three global warming Representative Concentration Pathways scenarios (i.e., 2.6, 4.5, and 8.5) based on mean climate data extracted from four Global Circulation Models (i.e., Beijing Climate Center, China, Commonwealth Scientific and Industrial Research Organization, Australia, Met Office Hadley Center, United Kingdom, and Norwegian Climate Center, Norway). For this purpose, the stochastic weather generator model (LARS – WG) and soil and water assessment tool (SWAT) were used. The hydrological model (SWAT) was calibrated and validated for 2001-2013 and 2014-2020, respectively. The performance of the swat model according to the four statistical parameters (i.e., coefficient of determination, Nash-Sutclife, Root mean square error to the standard deviation, and percent bias test) was classified as very good for two calibration and validation processes. Additionally, results showed that the mean temperature would probably rise by 1.3, 2.4, and 4.5°C under RCP 2.6, RCP 4.5, and RCP 8.5 at the end of this century, respectively. At the end of the century, the simulated average annual precipitation decreased from 772 mm/y to 756.7 and 741.6 mm/y under RCP4.5 and RCP8.5, respectively. In contrast, under the RCP2.6 scenario, the mean annual precipitation increased to 803 mm/year. As a result, the projected mean annual streamflow decreased from 501.52 m3/s to 429.7, 391.9, and 376.6 m3/s at the end of the century under RCP2.6, RCP4.5, and RCP8.5, respectively. Finally, the study region will potentially face water shortage due to climate change, exacerbated by population growth and increased water demands from agriculture and municipalities. Therefore, this paper emphasizes the need for reevaluating and adapting to accommodate changing streamflow patterns, ensuring a sustainable water supply for human needs while protecting the environment.

The urgency to attenuate techno-economic and ecological threats constituted by chemical admixtures has necessitated the adoption of feasible natural admixtures. The chemical interaction of admixtures with concrete ingredients affects concrete's plastic and hardened structure. The impact of concrete properties on construction works is of great concern to engineers as it plays a vital role towards viable infrastructural development. This study focused on developing an eco-friendly, sustainable structural concrete using potato starch (PS) as an admixture. PS has been included to in concrete in discrete percentages (0%, 0.4%, 0.8%, 1.2%, 1.6%, 2.0%) of cement weight employing mix ratios of 1: 1.5: 2, 1:2:4, 1:3:6 and water-cement ratio of 0.6. This study evaluates the effect of PS-admixture on concrete properties in the plastic state (setting time and workability) and at the hardened state (compressive strength) at 7, 21, 28, 56, and 90 days of curing. Potato starch (PS) admixture showed higher compressive strengths in concrete mixes with lower ratios (1:2:4 and 1:3:6). The strength test results for the 1:1.5:2, 1:2:4 and 1:3:6 mix ratios show a maximum strength of 32.77 N/mm2, 35.12 N/mm2 and 38.97 N/mm2 respectively for 28 curing days, at 1.2% PS addition, after which there was a strength-reduction. Rise A rise in the percentage inclusion of PS boosts the setting- time of cement paste and compressive strength. An optimal- percentage of 1.2% PS by cement- weight is advised for reliable concrete strength performance. Utilization of PS in concrete is recommended and should be embraced, considering its low- cost, availability, environmental amicability, and ability to enhance structural durability.

This study focuses on PET waste reduction worldwide by looking at the application of these polymeric materials in the construction and building industries. An effective application of PET wastes will reduce PET pollution, especially in water bodies. Due to its rising cost, it can partially replace the conventional binder used (cement).Bricks were made in the conventional cement sand and PET sand, and a total of 72 cubes were produced for different mix ratios of 1:1, 1.5:1, and 2:1. Their properties like particle size analysis, water absorption, slump testing, and compressive strength were investigated and compared.The particle size analysis showed that the sand was well graded with a Cu of 3.41 and a Cc of 1.07. The results of the water absorption test showed that, in both series and different mix ratios, the PET sand interlocking blocks had a lower sorptivity (percentages of 2.02, 2.72, and 4.20) than the cement sand interlocking blocks (percentages of 0.91, 2.40, and 3.31). The mixtures produced a 70 mm, 50 mm, and 80 mm slump for 1:1, 1.5:1, and 2:1, respectively.The maximum compressive strengths in cement sand interlocking blocks were 13.89 N/mm2, 17.34 N/mm2, and 21.06 N/mm2 in the 1:1, 1.5:1, and 2:1 respectively. Although the results showed that the compressive strength of PET sand interlocking bricks was lower than that of cement sand interlocking bricks, it can be useful in a low density carriage road.

Image classification depends substantially on the remote sensing method to generate maps of land use and land cover. This study used machine learning algorithms for classifying land cover, evaluating algorithms, and choosing the best way based on accuracy assessment matrices for land cover classifications. Satellite images from the Landsat by the United States Geological Survey (USGS) were used to classify the Babylon Governorate Land Use Land Cover (LULC). This study employed multispectral satellite images utilizing a spatial resolution of 30 meters and organized the data using three different algorithms to see the most accuracy. The process of categorization was carried out with the use of three distinct algorithms, which are as follows: Support Vector Machine (SVM), Mahalanobis Distance (MD), and Maximum Likelihood Classification (MLC). The classification algorithms utilized ArcGIS 10.8 and ENVI 5.3 software to detect four LULC classes: (Built-up Land, Water, Barren Land, and Agricultural Land). When applied to Landsat images, the results showed that the SVM approach gives greater overall accuracy and a larger kappa coefficient than the MD and MLC methods. SVM, MD, and MLC algorithms each have respective overall accuracy values of 86.88%, 85.00%, and 79.38%, respectively

One of the most important construction activities worldwide is the construction using autoclaved aerated concrete units at the global level is increasing significantly and the use of these units leads to the consumption of large amounts of resources and causes large residues waste, which leads to great damage to the environment and significant economic losses for companies and people. In recent periods, a noticeable increase has been observed in the manufacture of building units in Iraq. Iraqi factories have been affected by the waste resulting from manufacturing processes. The main objective of the study is to utilize tons of waste caused by the process of manufacturing AAC block in many Iraqi factories and turn it into a high-quality, environmentally friendly, and economical cement-based polymer-modified adhesive. The experimental part was carried out by preparing the product first and then studying properties according to international standards, SEM, EDS, mapping, and other techniques have been used to characterize the prepared samples. The adhesive properties were strongly affected by autoclaved aerated waste powder. Excellent bond strength exceeded the standard by 30%. Building units had 50% higher adhesion and 30% higher tensile strength than standard. Compared to market adhesive, the study adhesive has better properties. As for the economic factor, using waste in adhesive manufacturing reduced the price of 1 m3 by 15% compared to the reference mixture, but the study's adhesive was at least 40% cheaper than imported adhesives.

The generation of wastewater or effluent is unavoidable as long as humans exist, and it could cause potential danger if not properly managed. One way to manage it is by ensuring proper treatment before discharging into rivers, streams, and creeks. This will not just protect human health but will also protect aquatic fauna and flora. Thus, this research applied scientific and engineering principles to design a waste stabilization pond (WSP) to treat municipal effluent generated in a large military community (Sobi Cantonment), which currently lacks a wastewater treatment plant. The research revealed that the WSP will comprise two anaerobic ponds, one facultative pond, and two maturation ponds, all arranged in series with the addition of two (in series) anaerobic ponds as standby, arranged in parallel with the other set of anaerobic ponds. The research further revealed that the sludge accumulation rate at the primary anaerobic pond is 135 m3 per year, requiring a desludging frequency of 2.8 years. However, the retention time of the anaerobic, facultative, and maturation ponds were 3.9 days, 10.7 days, and 8 days, respectively. Also, the diameter of the inlet and outlet pipes was designed to be 3 inches. while the required land area (including additional space for personnel accessibility during maintenance) is approximately one hectare. Both orthographic and isometric drawings of the WSP were provided in detail. It was concluded that the designed WSP would highly comply with both WHO and FEPA effluent discharge standards regarding BOD and faecal coliform.

Due to the scarcity of experimental laboratory research on the effect of repetitive stress resulting from the railway on retaining walls, this study presents an investigation of an experimental laboratory model to study the effect of repetitive loads resulting from the railway on the adjacent retaining wall through several factors. The results of an experimental investigation of horizontal displacements of steel sheet pile walls behind excavations in the sand adjacent to railway tracks are presented. A series of model tests have been carried out in which the effect of sand density, horizontal distance between the railway and the sheet wall, and dynamic load amplitude on the wall horizontal dynamic displacement and its relationship to the railway dynamic vertical settlement were investigated with a load frequency equal to 2 Hz. The study examines various parameters, including different relative densities (30% loose, 55% medium, and 75% dense sand), different distances between the railway and retaining wall (0.5 H, 1 H, and 1.5 H), and variations in burden amplitudes (0.22, 0.44, and 0.66 tons). The most important factor that affects the dynamic displacement ratio (D/H) value is the relative density of the soil. The dynamic displacement ratio inversely correlates with the horizontal distance separating the railway and the retaining wall. The displacement ratio experienced a reduction of approximately 30% and 23% when the railway location relative to the retaining wall shifted from 0.5H to 1H and from 1 H to 1.5 H, respectively. The displacement ratio is directly proportional to the amplitude of cyclic live loading. Ultimately, using dense backfill soil enhances efficiency, resulting in decreased settlement of the railway and improved performance of the nearby retaining walls. It should be noted that there is a direct correlation between the horizontal movement of the wall and the vertical settlement of the rail. In the case of dense soil, these values are closely aligned.

Makhool Dam is a proposed structure on the Tigris River in the Salah al-Din Governorate, northwest of Baiji. The reservoir's sediment sources encompass the Tigris River, the Greater Zab River, and the Lesser Zab River. Climate change exerts a significant influence on both sediment accumulation within the dam reservoir and associated water resources. This paper specifically investigates the impact of climate change on sediment dynamics within the Makhool Dam reservoir. HEC-RAS 6.3.1 has been used to simulate the sediment dynamics and flow for the three rivers entering the reservoir. The SSP2-4.5 and SSP5-8.5 emission scenarios were applied to the 2021-2040, 2041-2060, 2061-2080, and 2081-2100 of 2021–2100. The calibration process of the model was performed using recorded water surface elevation measurements. The model was validated using the sediment concentrations at the proposed Makhool Dam. The sediment mass decreases along the rivers from upstream to downstream. The sediment mass is anticipated to decrease by approximately 20% and 35% from 2021 to 2100 under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. For the studied future period, the estimated annual sediment deposition under the SSP2-4.5 and SSP5-8.5 scenarios is around 22×106 tons and 19×106 tons, respectively. In addition, under these scenarios, the potential life of the Makhool Reservoir is expected to be 95.7 and 109.5 years, respectively. The findings of this paper can play a vital role in supporting planners and decision-makers in performing efficient strategies for climate change adaptation and mitigating the impact of climate change.